Nicholas will tell you that I was extremely skeptical of the oven heating trick when assembling the GUS prototype, but I'm convinced - it really does work. I prefer the hair dryer to the oven, though, both for finer control and keeping the heating concentrated on the area that needs it.

My backup plan was a heat gun. I have a "hobby" one that is meant for shrinking model airplane covering, I think it would have worked well. Then there is our industrial one, Master Appliance brand, lowest temp is 200F, some models go up to 1000F. It would make quick work of PLA Really, though, there was very little to do before the bearings would just "pop" in.

I would suggest freezing the bearing if it was an interference fit with ductile and/or strong enough metal. The plastic is low strength and fairly brittle. What I like about using heat to get the bearing into its socket is that it relaxes the part.

One of my compadres at Speco was busy inventing problems for our Wally build, and pointed out something interesting. It seems that if there is any variation in the length of the arms for the Z axis mechanism, "interesting" things will happen to the bed as it moves up and down.

So, I got curious, and wanted to see where we stood with respect to arm length variation -

Measuring across pins

IMG_1722_1.jpg (105.71 KiB) Viewed 59429 times

Turns out that I was able to find four arms that measured to within .001" of each other! I didn't expect that, but it means that at least for us there is no problem . Bearing alignment is very good too, most of them are dead nuts on (technical term), a few are a little stiff. This was done with .314 pins, .315 was no-go.

We're finally making some progress ! At least, we're simulating making some progress

Before we put a new job in one of the machining centers, Orlando, our part programming guru, runs a simulation of the g code to verify it. The simulation includes a high fidelity model of the machine tool, including fixtures. If there is a bug in the code, much better to crash into a simulated fixture than a real one.

This is the first operation for Battleship Wally's backboard.

Last edited by smooshed on Mon Jan 27, 2014 1:56 pm, edited 1 time in total.